1. Field of the Invention
The present invention relates to a method and an apparatus for controlling a motor, and more particularly to, a method and an apparatus for controlling a motor that reduce vibrations and noises caused when the motor is started.
2. Description of the Related Art
Generally, an apparatus for controlling a motor forcibly rotates a rotor at a fixed rotation speed when a motor is to be started, and detects a position of the rotor after a predetermined time to control the driving (the number of revolutions, etc.) of the motor. However, such a structure causes vibrations and noises when the motor is started.
A conventional technology concerning this problem is disclosed in Japanese Patent Application Laid-Open No. 2002-252996. In the conventional technology, an apparatus for controlling a synchronous motor includes a direct-current power supply, an output unit that energizes stator coils of plural phases from a direct current voltage, and an inverter device that drives the synchronous motor by switching energizing phase. The inverter device includes an inverter circuit, a control circuit, a driver that drives the inverter circuit, and a rotor data detector. The control circuit includes a starting processor, an energizing-phase setting unit, a switching unit, a speed controller, and a drive-signal generating unit. An energizing phase signal to be outputted from the starting processor to the energizing-phase setting unit includes first to third energizing patterns that are successively applied when the synchronous motor is started. There is a relationship of T1>T3≧T2≧0, where a first energizing period is T1, a second energizing period is T2, and a third energizing period is T3.